During fabrication of a semiconductor wafer, chemical mechanical polishing is performed to smooth surfaces of the semiconductor wafer using chemical and mechanical forces. For example, the semiconductor wafer is polished to prepare the semiconductor wafer for a new layer of material. In an example of polishing, the semiconductor wafer is secured to a polishing head configured to polish the semiconductor wafer against a polishing pad (e.g., vacuum pressure is used to secure the semiconductor wafer to the polishing head). The polishing head applies force to the semiconductor wafer toward the polishing pad during polishing. The polishing head rotates the semiconductor wafer against the polishing pad, which is also rotated, to apply mechanical force to the semiconductor wafer to remove material or even out irregular topography of the semiconductor wafer. In an example, chemicals are applied to the polishing pad during polishing to apply corrosive chemical force to the semiconductor wafer to aid in polishing.